The present invention relates to a laminated structure for use as sports equipment incorporating a strong, resilient, flexible board, plank or sheet structure and its method of manufacture. More particularly, the invention relates to a composite structure including natural fibrous material such as bamboo for fabricating sports boards such as skateboard decks and the process for constructing such sports boards.
There are numerous types of boards used for sports which are fabricated from solid and, more commonly, composite board structures. This class of equipment is herein referred to as sports boards and includes but is not limited to skateboard decks, snow boards, skim boards without foam cores, wake boards, wave boards, kite boards, snow-skateboards, sail boards, micro-skis, and snow skis. Each of these articles is constructed from a substantially planar structure commonly formed by laminating multiple layers of natural and/or man-made materials into a composite material that is strong, resilient and flexible. Composites for a skateboard decks, including wood or plastic for example, are flexible enough to withstand the dynamic forces exerted on it by the user without breaking and without significant degradation of the board""s xe2x80x9cmemory,xe2x80x9d i.e. the ability to return to its original form after flexing without degradation.
In addition to being strong, resilient and flexible, sports boards should be light weight, impact resistant, inexpensive, easy to work with, lend themselves to non-planar shapes and curves, be environmentally friendly and aesthetically pleasing.
One prior art skateboard is sold by BAMBUSA(trademark) of San Diego, Calif. The skateboard deck appears in plan view to include numerous strips of bamboo that run the length of the deck. The bamboo strips are approximately one inch wide and adjacently abutted to create joints that run from the front of the board to the tail. The skateboard is also advertised as being comprised of xe2x80x9c100% bamboo.xe2x80x9d With a solid bamboo core and exterior, this deck teaches away from the use of xe2x80x9csandwichxe2x80x9d construction techniques that employ strong outer layers with a light-weight interior core. The resulting BAMBUSA(trademark) skateboard deck is relatively heavy and more rigid than the present invention for a given board width and thickness.
Co-pending PCT application no. PCT/AU01/00253 discloses a watercraft such as a surfboard comprising a foam inner core and an outer layer of bamboo veneer. The PCT application does not disclose the use of structural layers of strong, resilient material comprised of natural fiber-embedded-matrix or the manner of joining sheets of these materials to create structural layers for use with composite sports board of the present invention. In addition, the foam inner core of the PCT application is necessary to enhance the watercraft""s buoyancy but is generally less resilient than the materials conventionally employed in the fabrication of skateboard decks and is unacceptable for such use. The PCT application does not disclose or suggest the use of these more resilient and more flexible composite materials which are important in fabricating skateboards with suitable flex-pop and memory.
The present invention relates to a composite sports board and its method of fabrication. The board is comprised of a first structural layer of a strong, resilient material comprised of natural fiber-embedded-matrix; a second structural layer optionally, albeit preferably, constructed from the said strong, resilient material; a flexible core interposed between the first and second structural layers; an adhesive for fixedly attaching the first and second structural layers to the core. The board may be adapted to receive one or more additional accessories suited for the particular type of sports board. For example, the sports board may include means for mounting wheels as in the case of a skateboard; means for mounting bindings as in the case of a snow ski, micro-ski, snow board, kite board, wake board, sail board, or water ski; or means for mounting a paddle or accommodating a seat as in the case of a wave ski.
The strong, resilient material comprised of natural fiber-embedded-matrix of the present invention includes organic materials having bundles of cellulose fibers embedded in a matrix such as pectin. In some embodiments, the strong, resilient material is a grass such as bamboo. Some species of bamboo including Moso, D. asper, B. blumeana, and D. latiflorus are particularly well suited for board construction because of their strength-to-weight ratio and resilience under abusive riding conditions. Although subject to variation depending on the application, the bamboo component of the skateboard deck of the preferred embodiment is a veneer between 0.1 and 1.5 mil in thickness. The one or more plies of the core may be selected from a wide variety of natural and man-made products that are relatively light and flexible, including plastics and woods such as Canadian Maple.
In some embodiments, the bamboo veneer is fabricated from a plurality of bamboo sheets that are xe2x80x9cpealedxe2x80x9d or turned from a pole of bamboo. These sheets may be trimmed at or near a point corresponding to the node of the bamboo pole. The individual sheets when bonded together and applied to the deck of the preferred embodiment may have an overlapping joint that runs laterally across the width of the board. The result is a relatively large, continuous sheet of bamboo veneer that is capable of being used as a structural or weight bearing member in the composite board of the present invention while preserving the aesthetic appeal of the natural bamboo.
The use of a natural fiber-embedded-matrix such as bamboo as the primary structural or weight bearing member results in a composite sports board that is strong and light, exhibits better xe2x80x9cflex-popxe2x80x9d and memory, is more resilient, more environmentally friendly and derived from a more renewable resource than existing composite boards. Pop is the ability of the board to flexibly spring under load and maintain a high recoil speed with minimal fatigue.